After completing her PhD, Maher was made a
Natural Environment Research Council (NERC)
Fellow at the
Department of Geophysics, University of Edinburgh. She joined the
School of Environmental Sciences, University of East Anglia as a lecturer in 1987 and was promoted to Senior Lecturer in 1996 and Reader in 1998. Using her understanding of magnetic mineral formation in soils, she evaluated the paleo-climate of the
Chinese Loess Plateau. She developed spatial and temporal reconstructions of the Asian palaeo
monsoon. She was the
Royal Institution Scientists for the new century lecturer in 1999. Maher also studies
magnetic nanoparticles to track dust impacts on
climate change and changes in human health due to particulate air pollution. She was described by Richard Harrison as having "single-handedly developed the field of environmental magnetism". She demonstrated that soils that were exposed to higher rainfall make more
magnetite. She launched the Quantifying Uncertainty in the Earth System (QUEST) Working Group on Dust in 2008. Maher became interested in metal-rich particulate pollution. In 2013 Maher demonstrated that
silver birch trees could be used as pollution filters. The result was part of an investigation into the impact of roadside trees on the concentration of particulate matter found in people's homes. Silver birch trees are covered in tiny hairs, which can trap the particulate matter whilst allowing clean air to circulate. They found that the pollution collected in houses protected by silver birch trees was 50 - 60% lower than in houses without them. In 2016 Maher found toxic, metal-rich nanoparticles in human
brain tissue. By studying the nanoparticles using an
electron microscope, Maher found they were small and round, some with surface crystallites, indicating that they had been formed at high temperatures, rather than in the brain itself. The nanoparticles comprise a mix of iron-rich, strongly magnetic particles associated with other metals, including platinum, cobalt, aluminium and titanium. Similar metal-rich nanoparticles occur in abundance in urban air pollution, especially at busy roadsides. As the nanoparticles have diameters that are less than 200 nm, they can enter the brain via the lungs and blood circulation, via ingestion and transport through the neuroenteric system, and through the
olfactory nerve.
Magnetite can produce
reactive oxygen species in the brain. Her work on air pollution nanoparticles in human tissues attracts worldwide scientific, and media, attention. She has appeared on numerous BBC News and World Service TV and radio programmes, including
BBC Radio 4's
Inside Science in 2018, discussing the
Government of the United Kingdom Clean Air Strategy. S == Awards and honours ==